// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/quic/crypto/aes_128_gcm_12_encrypter.h"

#include <memory>

#include "net/quic/quic_utils.h"
#include "net/quic/test_tools/quic_test_utils.h"

using base::StringPiece;
using std::string;

namespace {

// The AES GCM test vectors come from the file gcmEncryptExtIV128.rsp
// downloaded from http://csrc.nist.gov/groups/STM/cavp/index.html on
// 2013-02-01. The test vectors in that file look like this:
//
// [Keylen = 128]
// [IVlen = 96]
// [PTlen = 0]
// [AADlen = 0]
// [Taglen = 128]
//
// Count = 0
// Key = 11754cd72aec309bf52f7687212e8957
// IV = 3c819d9a9bed087615030b65
// PT =
// AAD =
// CT =
// Tag = 250327c674aaf477aef2675748cf6971
//
// Count = 1
// Key = ca47248ac0b6f8372a97ac43508308ed
// IV = ffd2b598feabc9019262d2be
// PT =
// AAD =
// CT =
// Tag = 60d20404af527d248d893ae495707d1a
//
// ...
//
// The gcmEncryptExtIV128.rsp file is huge (2.8 MB), so I selected just a
// few test vectors for this unit test.

// Describes a group of test vectors that all have a given key length, IV
// length, plaintext length, AAD length, and tag length.
struct TestGroupInfo {
    size_t key_len;
    size_t iv_len;
    size_t pt_len;
    size_t aad_len;
    size_t tag_len;
};

// Each test vector consists of six strings of lowercase hexadecimal digits.
// The strings may be empty (zero length). A test vector with a nullptr |key|
// marks the end of an array of test vectors.
struct TestVector {
    const char* key;
    const char* iv;
    const char* pt;
    const char* aad;
    const char* ct;
    const char* tag;
};

const TestGroupInfo test_group_info[] = {
    { 128, 96, 0, 0, 128 },
    { 128, 96, 0, 128, 128 },
    { 128, 96, 128, 0, 128 },
    { 128, 96, 408, 160, 128 },
    { 128, 96, 408, 720, 128 },
    { 128, 96, 104, 0, 128 },
};

const TestVector test_group_0[] = {
    { "11754cd72aec309bf52f7687212e8957", "3c819d9a9bed087615030b65", "", "", "",
        "250327c674aaf477aef2675748cf6971" },
    { "ca47248ac0b6f8372a97ac43508308ed", "ffd2b598feabc9019262d2be", "", "", "",
        "60d20404af527d248d893ae495707d1a" },
    { nullptr }
};

const TestVector test_group_1[] = {
    { "77be63708971c4e240d1cb79e8d77feb", "e0e00f19fed7ba0136a797f3", "",
        "7a43ec1d9c0a5a78a0b16533a6213cab", "",
        "209fcc8d3675ed938e9c7166709dd946" },
    { "7680c5d3ca6154758e510f4d25b98820", "f8f105f9c3df4965780321f8", "",
        "c94c410194c765e3dcc7964379758ed3", "",
        "94dca8edfcf90bb74b153c8d48a17930" },
    { nullptr }
};

const TestVector test_group_2[] = {
    { "7fddb57453c241d03efbed3ac44e371c", "ee283a3fc75575e33efd4887",
        "d5de42b461646c255c87bd2962d3b9a2", "", "2ccda4a5415cb91e135c2a0f78c9b2fd",
        "b36d1df9b9d5e596f83e8b7f52971cb3" },
    { "ab72c77b97cb5fe9a382d9fe81ffdbed", "54cc7dc2c37ec006bcc6d1da",
        "007c5e5b3e59df24a7c355584fc1518d", "", "0e1bde206a07a9c2c1b65300f8c64997",
        "2b4401346697138c7a4891ee59867d0c" },
    { nullptr }
};

const TestVector test_group_3[] = {
    { "fe47fcce5fc32665d2ae399e4eec72ba", "5adb9609dbaeb58cbd6e7275",
        "7c0e88c88899a779228465074797cd4c2e1498d259b54390b85e3eef1c02df60e743f1"
        "b840382c4bccaf3bafb4ca8429bea063",
        "88319d6e1d3ffa5f987199166c8a9b56c2aeba5a",
        "98f4826f05a265e6dd2be82db241c0fbbbf9ffb1c173aa83964b7cf539304373636525"
        "3ddbc5db8778371495da76d269e5db3e",
        "291ef1982e4defedaa2249f898556b47" },
    { "ec0c2ba17aa95cd6afffe949da9cc3a8", "296bce5b50b7d66096d627ef",
        "b85b3753535b825cbe5f632c0b843c741351f18aa484281aebec2f45bb9eea2d79d987"
        "b764b9611f6c0f8641843d5d58f3a242",
        "f8d00f05d22bf68599bcdeb131292ad6e2df5d14",
        "a7443d31c26bdf2a1c945e29ee4bd344a99cfaf3aa71f8b3f191f83c2adfc7a0716299"
        "5506fde6309ffc19e716eddf1a828c5a",
        "890147971946b627c40016da1ecf3e77" },
    { nullptr }
};

const TestVector test_group_4[] = {
    { "2c1f21cf0f6fb3661943155c3e3d8492", "23cb5ff362e22426984d1907",
        "42f758836986954db44bf37c6ef5e4ac0adaf38f27252a1b82d02ea949c8a1a2dbc0d6"
        "8b5615ba7c1220ff6510e259f06655d8",
        "5d3624879d35e46849953e45a32a624d6a6c536ed9857c613b572b0333e701557a713e"
        "3f010ecdf9a6bd6c9e3e44b065208645aff4aabee611b391528514170084ccf587177f"
        "4488f33cfb5e979e42b6e1cfc0a60238982a7aec",
        "81824f0e0d523db30d3da369fdc0d60894c7a0a20646dd015073ad2732bd989b14a222"
        "b6ad57af43e1895df9dca2a5344a62cc",
        "57a3ee28136e94c74838997ae9823f3a" },
    { "d9f7d2411091f947b4d6f1e2d1f0fb2e", "e1934f5db57cc983e6b180e7",
        "73ed042327f70fe9c572a61545eda8b2a0c6e1d6c291ef19248e973aee6c312012f490"
        "c2c6f6166f4a59431e182663fcaea05a",
        "0a8a18a7150e940c3d87b38e73baee9a5c049ee21795663e264b694a949822b639092d"
        "0e67015e86363583fcf0ca645af9f43375f05fdb4ce84f411dcbca73c2220dea03a201"
        "15d2e51398344b16bee1ed7c499b353d6c597af8",
        "aaadbd5c92e9151ce3db7210b8714126b73e43436d242677afa50384f2149b831f1d57"
        "3c7891c2a91fbc48db29967ec9542b23",
        "21b51ca862cb637cdd03b99a0f93b134" },
    { nullptr }
};

const TestVector test_group_5[] = {
    { "fe9bb47deb3a61e423c2231841cfd1fb", "4d328eb776f500a2f7fb47aa",
        "f1cc3818e421876bb6b8bbd6c9", "", "b88c5c1977b35b517b0aeae967",
        "43fd4727fe5cdb4b5b42818dea7ef8c9" },
    { "6703df3701a7f54911ca72e24dca046a", "12823ab601c350ea4bc2488c",
        "793cd125b0b84a043e3ac67717", "", "b2051c80014f42f08735a7b0cd",
        "38e6bcd29962e5f2c13626b85a877101" },
    { nullptr }
};

const TestVector* const test_group_array[] = {
    test_group_0,
    test_group_1,
    test_group_2,
    test_group_3,
    test_group_4,
    test_group_5,
};

} // namespace

namespace net {
namespace test {

    // EncryptWithNonce wraps the |Encrypt| method of |encrypter| to allow passing
    // in an nonce and also to allocate the buffer needed for the ciphertext.
    QuicData* EncryptWithNonce(Aes128Gcm12Encrypter* encrypter,
        StringPiece nonce,
        StringPiece associated_data,
        StringPiece plaintext)
    {
        size_t ciphertext_size = encrypter->GetCiphertextSize(plaintext.length());
        std::unique_ptr<char[]> ciphertext(new char[ciphertext_size]);

        if (!encrypter->Encrypt(nonce, associated_data, plaintext,
                reinterpret_cast<unsigned char*>(ciphertext.get()))) {
            return nullptr;
        }

        return new QuicData(ciphertext.release(), ciphertext_size, true);
    }

    TEST(Aes128Gcm12EncrypterTest, Encrypt)
    {
        for (size_t i = 0; i < arraysize(test_group_array); i++) {
            SCOPED_TRACE(i);
            const TestVector* test_vectors = test_group_array[i];
            const TestGroupInfo& test_info = test_group_info[i];
            for (size_t j = 0; test_vectors[j].key != nullptr; j++) {
                // Decode the test vector.
                string key = QuicUtils::HexDecode(test_vectors[j].key);
                string iv = QuicUtils::HexDecode(test_vectors[j].iv);
                string pt = QuicUtils::HexDecode(test_vectors[j].pt);
                string aad = QuicUtils::HexDecode(test_vectors[j].aad);
                string ct = QuicUtils::HexDecode(test_vectors[j].ct);
                string tag = QuicUtils::HexDecode(test_vectors[j].tag);

                // The test vector's lengths should look sane. Note that the lengths
                // in |test_info| are in bits.
                EXPECT_EQ(test_info.key_len, key.length() * 8);
                EXPECT_EQ(test_info.iv_len, iv.length() * 8);
                EXPECT_EQ(test_info.pt_len, pt.length() * 8);
                EXPECT_EQ(test_info.aad_len, aad.length() * 8);
                EXPECT_EQ(test_info.pt_len, ct.length() * 8);
                EXPECT_EQ(test_info.tag_len, tag.length() * 8);

                Aes128Gcm12Encrypter encrypter;
                ASSERT_TRUE(encrypter.SetKey(key));
                std::unique_ptr<QuicData> encrypted(EncryptWithNonce(
                    &encrypter, iv,
                    // This deliberately tests that the encrypter can handle an AAD that
                    // is set to nullptr, as opposed to a zero-length, non-nullptr
                    // pointer.
                    aad.length() ? aad : StringPiece(), pt));
                ASSERT_TRUE(encrypted.get());

                // The test vectors have 16 byte authenticators but this code only uses
                // the first 12.
                ASSERT_LE(static_cast<size_t>(Aes128Gcm12Encrypter::kAuthTagSize),
                    tag.length());
                tag.resize(Aes128Gcm12Encrypter::kAuthTagSize);

                ASSERT_EQ(ct.length() + tag.length(), encrypted->length());
                test::CompareCharArraysWithHexError("ciphertext", encrypted->data(),
                    ct.length(), ct.data(), ct.length());
                test::CompareCharArraysWithHexError(
                    "authentication tag", encrypted->data() + ct.length(), tag.length(),
                    tag.data(), tag.length());
            }
        }
    }

    TEST(Aes128Gcm12EncrypterTest, GetMaxPlaintextSize)
    {
        Aes128Gcm12Encrypter encrypter;
        EXPECT_EQ(1000u, encrypter.GetMaxPlaintextSize(1012));
        EXPECT_EQ(100u, encrypter.GetMaxPlaintextSize(112));
        EXPECT_EQ(10u, encrypter.GetMaxPlaintextSize(22));
    }

    TEST(Aes128Gcm12EncrypterTest, GetCiphertextSize)
    {
        Aes128Gcm12Encrypter encrypter;
        EXPECT_EQ(1012u, encrypter.GetCiphertextSize(1000));
        EXPECT_EQ(112u, encrypter.GetCiphertextSize(100));
        EXPECT_EQ(22u, encrypter.GetCiphertextSize(10));
    }

} // namespace test
} // namespace net
